问题 选择题

在经常刮大风的海岛上,无翅或残翅的昆虫较多.产生这种现象的主要原因是(  )

A.不适应的结果

B.自然选择

C.人工选择

D.遗传和变异

答案

在经常刮大风的海岛上,生活着的昆虫多是无翅或残翅的类型,这是自然选择的结果.由于这些海岛上经常刮大风,哪些有翅能飞但翅膀不够强大的昆虫,就常常被大风吹到海里,因而生存和繁殖后代的机会较少.而无翅或残翅的昆虫,由于不能飞翔,就不容易被风吹到海里,因而生存和繁殖后代的机会就多.经过一段时间的自然选择之后,岛上无翅的昆虫就特别多.因此,产生这种现象的主要原因自然选择.

故选B.

解答题
阅读理解

阅读理解。

     下面是一篇杂志文章,请将标有A--F的句子插入文章中标号为1--5的合适位置,使这篇文章意义完整,结构连贯,其中有一个句子是多余的。

     As we know, the concept of the Beijing 2008 Olympic Games is "Green Olympics, High-tech Olympics and

People's Olympics."  1  . Among them "Green Olympics" embraces the essence of the 3000-year long Chinese

philosophy, namely harmony and unity of nature and human existence.

     On the World Environment Day in 2003, Beijing Organizing Committee for the 2008 Olympic Game began

the Green Office Project.   2  .

     On September 24, 2005, the logo of the Green Olympics was shown at the Beijing Young Palace.   3  . It

consists of the crown of a tree and the shape of a human being that are used to create the form of a large tree

reaching the sky. The image represents harmony and unity between human beings and nature. Just like swinging colored strips that surround and cross each other, the green lines form a crown of tree and recall flowers in full bloom, expressing the sustainable (可持续的) development of environment protection. 

       4  . Let's participate in green actions, such as beautifying the environment, protecting the environment and

saving resources.    5  .

A. No matter when it is, we need green space.

B. This concept includes three themes.

C. Let's carry the theme of Green Olympics through to the end.

D. The logo uses a form of the traditional handwriting.

E. The Beijing Olympic Games is a testimony of the fact that the world has its trust rested upon China.

F. It covers such areas as saving energy and water, trash classification, and use of office equipment, 

    paper recycling, paperless office work and the environmentally friendly behaviors of staff.